fixing unit

Author: chelsea-lin

bigframes/operations/strings.py

@@ -38,7 +38,7 @@
 class StringMethods(bigframes.operations.base.SeriesMethods, vendorstr.StringMethods):
     __doc__ = vendorstr.StringMethods.__doc__
 
-    def __getitem__(self, key: int | slice) -> series.Series:
+    def __getitem__(self, key: Union[int, slice]) -> series.Series:
         if isinstance(key, int):
             if key < 0:
                 raise NotImplementedError("Negative indexing is not supported.")

third_party/bigframes_vendored/pandas/core/strings/accessor.py

@@ -13,7 +13,7 @@ class StringMethods:
     R's stringr package.
     """
 
-    def __getitem__(self, key: int | slice):
+    def __getitem__(self, key: typing.Union[int, slice]):
         """
         Index or slice string or list in the Series.